Check your self service account to make sure it is active. Put SIM card in another unlocked phone to make sure it is the SIM card and not your phone. Have you tried rebooting, resetting network settings, reinstalling SIM card?
@abbigoodwin04 Use incognito/private mode and log into your account, select Quick Links (top right) and then Change SIM. You will need to verify via 2FA either when logging into the account or after the Change SIM process.
